 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  ******************************************************************************/

 package org.eclipse.ui.internal;

 import java.util.ArrayList ;
 import java.util.Iterator ;
 import java.util.List ;

 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.ui.internal.util.Util;

 /**
  * <p>
  * The SelectionConversionService is the service that converts the selection to
  * IResources.
  * </p>
  * <p>
  * This interface is only intended for use within the
  * <code>org.eclipse.ui.workbench</code> and <code>org.eclipse.ui.ide</code>
  * plug-ins.
  * </p>
  *
  * @since 3.2
  */
 public class SelectionConversionService implements ISelectionConversionService {

     /**
      * Attempt to convert the elements in the passed selection into resources by
      * asking each for its IResource property (iff it isn't already a resource).
      * If all elements in the initial selection can be converted to resources
      * then answer a new selection containing these resources; otherwise answer
      * an empty selection.
      *
      * @param originalSelection
      * the original selection
      * @return the converted selection or an empty selection.
      */
     public IStructuredSelection convertToResources(
             IStructuredSelection originalSelection) {
         // @issue resource-specific code should be pushed into IDE
 Class resourceClass = LegacyResourceSupport.getResourceClass();
         if (resourceClass == null) {
             return originalSelection;
         }

         List result = new ArrayList ();
         Iterator elements = originalSelection.iterator();

         while (elements.hasNext()) {
             Object currentElement = elements.next();
             Object resource = Util.getAdapter(currentElement, resourceClass);
             if (resource != null) {
                 result.add(resource);
             }
         }

         // all that can be converted are done, answer new selection
 if (result.isEmpty()) {
             return StructuredSelection.EMPTY;
         }
         return new StructuredSelection(result.toArray());
     }

 }

